Amana AMSS920803BN Error Code 3 Flashes: Pressure Switch Stuck Open
What Does Code 3 Flashes Mean?
Code 3 (3 Flashes) on the Amana AMSS920803BN indicates a pressure switch stuck open condition. The induced draft blower (inducer motor) is running, but the pressure switch has not closed to confirm proper exhaust venting. You will hear the inducer motor running continuously with no ignition.
The pressure switch is a safety device that verifies the inducer motor is creating enough negative pressure (draft) to safely vent combustion gases out of your home. If the switch does not close, the furnace will not allow gas to flow to the burners. This protects against dangerous exhaust gas buildup.
Common causes include a blocked, pinched, or disconnected pressure switch hose, a blocked exhaust flue or air intake pipe, a clogged condensate drain system that backs up and prevents proper airflow, or a weak inducer motor. Of these, a clogged condensate drain is the most accessible DIY fix for homeowners.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- Code 3 returns after clearing the condensate drain and checking vents
- The inducer motor sounds unusually loud, weak, or does not start at all
- You cannot locate or access the condensate drain
- You see water pooling around the furnace base
- The pressure switch hose appears disconnected or cracked
✓ Verified against manufacturer service manual — March 2026